Many electronic devices include acoustic devices such as microphones or speakers in order to record sound, output sound, and/or perform other functions. Many acoustic devices may include components that are sensitive to damage or impaired operation by exposure to liquids such as water. Such acoustic devices may be isolated in an electronic device from exposure to liquids from the external environment. However, in order to function many acoustic devices included in electronic device may require a through hole to an acoustic aperture of an electronic device that may expose the acoustic device to liquids from the external environment.
In some cases, acoustic devices may include a liquid resistant membrane separating the acoustic device from such a through hole. Such a liquid resistant membrane may allow sound waves to pass through but may restrict the passage of liquids present in the through hole. However, liquid present in the through hole may exert hydrostatic pressure on the liquid resistant membrane such that the liquid resistant membrane tears (allowing liquid into the acoustic device) and/or is restricted from vibrating such that sound waves are restricted from passing through and acoustic device operation is impaired.
Further, once liquid is present in the through hole, surface tension of the liquid and/or other pressures may restrict the ability of the liquid to exit. This phenomenon may exacerbate issues caused by entry of the liquid into the through hole.